Photobinding of ketoprofen in vitro and ex vivo

Ketoprofen (KP), a non-steroidal anti-inflammatory drug of the 2-aryl propionic class, has been shown to produce photoallergic side effects as well as cutaneous photosensitizing properties that induce other phototoxic effects. In the present study we investigated photobinding of ketoprofen to both human serum albumin (HSA), a model protein, and to ex vivo pig skin and its photodegradation. Results demonstrate that photoadduct formation and photodegradation progressively increased with irradiation time where they reach a maximum. Maximum photobinding to the viable layer of the epidermis was about 7-8% of the initial radiolabelled KP added, in the region of 15-30 min UV irradiation. These results were comparable to in vitro results that were seen with photobinding of KP to HSA; in this case, the quantity of covalently bound material was approximately 10% of the initial, after a maximum of 18 min irradiation. It was found by HPLC analysis that the KP decrease is accompanied by an increase of the corresponding photoproduct, decarboxylated ketoprofen (DKP). The yield of DKP reaches a maximum at around 15 min. DKP appears to play an important role in vitro and ex vivo, being the major photoproduct and responsible for the photobinding process. Using micro-autoradiographical techniques we investigated the penetration and distribution of ketoprofen in ex vivo pig skin in greater detail. It was apparent that percutaneous absorption was taking place and that most of the ketoprofen was predominately localised in fibroblasts in the papillary dermis. No other specific localisation within the skin architecture was identified. Although there were differences in the quantities of bound ketoprofen within the different layers of the skin, these levels did not appear to correlate with irradiation time.     

Reactions of (η6-Arene)tricarbonylchromium Complexes: Hydrogenation,Nitration, and Bromination

In this study, we explore the reactions of coordinated arenes, e.g., hydrogenation, nitration, and bromination, to prepare compounds which are not accessible from conventional organic synthesis. The reaction products formed from reactions with the coordinated and the uncoordinated arenes are compared. The polycyclic aromatic hydrocarbons (PAHs) employed for this study include phenanthrene, methyl- and acetyl-phenanthrene, and benz[a]anthracene (BA), The tricarbonylchromium group demonstrated various characteristics which influence the reactions in this work, such as an electronic effect to deactivate hydrogenation, a steric effect to exhibit, highly positional selective nitration, and a free radical mechanism to direct bromine to attack at the ring coordinated to tricarbonylchromium.     

Preparation,and infrared and thermal properties of six adducts of tetrakis-(8-hydroxyquinolinato)thorium(IV)

Six adducts of the tctrakis(8-hydroxyquinolinato) complex of thorium(IV) with 8-hydroxyquinoline, pyridine, urea, dimethylsulphoxide, dimethylformamide and 1,10-phenanthroline were prepared and characterized, the infrared bands for the room-temperature forms are given and their particular thermal properties are reported. The thermal analyses were performed mostly in the presence of air, but in some cases an argon atmosphere was used for comparison. The adducts were lost from the principal complex at temperatures varying between 110 and 290°. Intermediate oxygenated complexes were formed in each case at about 400°. The thermal data suggest the standardization of a procedure for the formation of Th(C₉H₆NO)₄.

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Zusammenfassung Sechs Addukte des Tetrakis(8-hydroxyquinolinato)-Komplexes von Thorium(IV) mit 8-Hydroxyquinolin, Pyridin, Harnstoff, Dimethylsulphoxid, Dimethylformamid und 1,10-Phenanthrolin wurden dargestellt und charakterisiert. Infrarotbanden und spezielle thermische Eigenschaften der Raumtemperatur-Formen sind angegeben. Die thermischen Analysen wurden meist in Luft ausgeführt, in einigen Fällen zu Vergleichszwecken aber auch in Argonatmosphäre. Die Addukte wurden vom Komplex bei Temperaturen zwischen 110 und 290 °C abgegeben. Intermediäre oxydierte Komplexe wurden in jedem Fall bei etwa 400 °C gebildet. Die thermischen Daten ermöglichen die Standardisierung eines Verfahrens zur Darstellung von Th(C₉H₆NO)₄.

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-(8- ) (IV) 8- , , , - , 1,10-. - , . , , . 110–290°. 400° . Th(C₉H₆NO)₄.

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We are grateful to the Bangladesh University Grants Commission for a Fellowship Grant to AR.     

Simple <Emphasis Type="Italic">b</Emphasis> ions have cyclic oxazolone structures. A neutralization-reionization mass spectrometric and computational study of oxazolone radicals

The 2-methyloxazol-5-on-2-yl radical (3) and its deuterium labeled analogs were generated in the gas-phase by femtosecond electron-transfer and studied by neutralization-reionization mass spectrometry and quantum chemical calculations. Radical 3 undergoes fast dissociation by ring opening and elimination of CO and CH(3)CO. Loss of hydrogen is less abundant and involves hydrogen atoms from both the ring and side-chain positions. The experimental results are corroborated by the analysis of the potential energy surface of the ground electronic state in 3 using density functional, perturbational, and coupled-cluster theories up to CCSD(T) and extrapolated to the 6-311 ++ G(3df,2p) basis set. RRKM calculations of radical dissociations gave branching ratios for loss of CO and H that were k(CO)/k(H) > 10 over an 80-300 kJ mol(-1) range of internal energies. The driving force for the dissociations of 3 is provided by large Franck-Condon effects on vertical neutralization and possibly from involvement of excited electronic states. Calculations also provided the adiabatic ionization energy of 3, IE(adiab) = 5.48 eV and vertical recombination energy of cation 3(+), RE(vert) = 4.70 eV. The present results strongly indicate that oxazolone structures can explain fragmentations of b-type peptide ions upon electron capture, contrary to previous speculations.     

Poly(choloyl)-based amphiphiles as pore-forming agents: transport-active monomers by design

This paper describes the design and synthesis of a family of pore-forming amphiphiles. Two of these amphiphiles, which are derived from cholic acid, lysine, and p-phenylenediamine, can produce pores in lipid bilayers as individual molecules. In sharp contrast, analogous amphiphiles that do not contain a rigid 1,4-phenylenediamide moiety favor the formation of dimer-based pores. Kinetic evidence in support of monomer- and dimer-based pores has been obtained from Na+ transport measurements across bilayers made from 1-palmitoyl-2-oleoyl-2-sn-glycero-3-phosphocholine (POPC). Structure-activity studies that have been carried out with pore-forming, dimer-based amphiphiles have also revealed a significant activity dependence on their overall compactness. The practical potential of pore-forming amphiphiles with controllable supramolecular properties is briefly discussed.     

Distance measurements between paramagnetic centers and a planar object by matrix Mims electron nuclear double resonance

Frequency-domain electron nuclear double resonance (ENDOR), two time-domain electron nuclear double resonance techniques, and electron spin echo envelope modulation spectroscopy are compared with respect to their merit in measurements of small hyperfine couplings to nuclei with intermediate gyromagnetic ratio such as 31P. The frequency-domain Mims ENDOR experiment is found to provide the most faithful line shapes. In the limit of long electron-nuclear distances of more than 0.5 nm, sensitivity of this experiment is optimized by matching the first interpulse delay to the transverse relaxation time of the electron spins. In the same limit, Mims ENDOR efficiency scales inversely with the sixth power of distance. Hyperfine splittings as small as 33 kHz can be detected, corresponding to an electron-31P distance of 1 nm. In systems, where a certain kind of nuclei is distributed in a plane, measurements of intermolecular hyperfine couplings can be analyzed in terms of a distance of closest approach of a paramagnetic center to that plane. By applying this technique to spin-labeled lipids in a fully hydrated lipid bilayer it is found that for a fraction of lipids, chain tilt angles can be 25 degrees larger than the mean tilt angle of the lipid chains. This model of all-trans hydrocarbon chains with a broad distribution of tilt angles is also consistent with orientation selection effects in high-field ENDOR spectra.     

Surface-enhanced Raman spectra study of metal complexes of N-D-glucosamine beta-naphthaldehyde and glycine and their interaction with DNA

Copper(II), zinc(II), cobalt(II) and cobalt(III) complexes of N-D-glucosamine beta-naphthaldehyde (C17H19O6N, NG) and glycine were synthesized. The four novel metal complexes, Cu(II)C19H28O11N2(CuGNG), Zn(II)C19H24O9N2 (ZnGNG), Co(II)C19H28O11N2(Co(II)GNG) and Co(III)C21H29O12N2(Co(III)GNG) were characterized by means of infrared (IR), electronic absorption spectroscopy and NMR etc. The surface-enhanced Raman spectra of the four complexes and their interaction with DNA were studied. By comparison of the surface-enhanced Raman spectra (SERS), the information of the four complexes' SER active sites and adsorption orientation were obtained. Combined with fluorescence spectra of Ethidium bromide (EthBr) DNA system, we concluded that none of the four complexes intercalate into DNA and that the presence of the glycine ligand lowered the anticancer activity of NG series complexes.     

1,3-Dipolar cycloaddition in the synthesis of pyrazolyl-substituted nitronyl nitroxides

A new approach to the synthesis of polyfunctional pyrazolyl-substituted nitronyl nitroxides was developed based on the presynthesized pyrazole derivatives prepared by 1,3-dipolar cycloaddition. The structures of the resulting mono-and biradicals were confirmed by X-ray diffraction. Dedicated to Academician A. L. Buchachenko on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2105–2116, September, 2005.     

Ion Association and Hydration in Aqueous Solutions of Nickel(II) and Cobalt(II) Sulfate

Aqueous solutions of nickel(II) and cobalt(II) sulfate have been investigated at 25 ^∘C by dielectric relaxation spectroscopy (DRS) over a wide range of frequencies (0.2 ≤ ν (GHz) ≤ 89) and salt concentrations (0.025 ≤ c(mol-L⁻¹) ≤ 1.4). The spectra indicate, as for MgSO₄(aq) studied previously, the simultaneous presence of double solvent-separated, solvent-shared and contact ion pairs in both NiSO₄(aq) and CoSO₄(aq). The stepwise formation constants for each ion-pair type and the overall association constant, obtained from the data are in good agreement with ultrasonic relaxation and other estimates. The DR spectra at higher concentrations (c ≥ 0.5 mol-L⁻¹) suggest the existence of a nonlinear triple ion M₂SO₄²⁺(aq). Consistent with the very strong hydration of the salts, which have ‘effective’ hydration numbers approaching 27 at infinite dilution, there are no significant differences in any of the relaxation or thermodynamic parameters for NiSO₄(aq) and CoSO₄(aq), except that the triple ion appears to be somewhat more stable for the latter.     

Ultrafast detection of microsatellite repeat polymorphism in endothelin 1 gene by electrophoresis in short capillaries

The methodology and instrumentation for fast denaturing electrophoresis in short capillaries was developed and exemplified by detection of short tandem repeat polymorphism in the endothelin 1 gene. The resolution of two nucleotides, which is required for the detection of a dinucleotide repeat polymorphism, was achieved in a capillary of an effective length of 2.5 cm at a temperature of 600C and an electric field strength of 600 V/cm in 42 s. Thus, the use of denaturing electrophoresis in short capillaries with laser-induced fluorescence detection resulted in a reduction of analysis time by a factor of 200 when compared to the conventional slab gel electrophoresis. The developed methodology and instrumentation is advantageous for an implementation in clinical diagnostics and genetic population screening where fast analytical instrumentation amenable to automation is of paramount importance.